

function array(n) {
    for (var i = 0; i < n; i++) this[i] = 0;
    this.length = n;
}

/* Quelques fonctions fondamentales doivent ¨ºtre transform¨¦es ¨¤ cause  
 * d'erreurs Javascript.  
 * Essayez par exemple de calculer 0xffffffff >> 4 ...  
 * Les fonctions utilis¨¦es maintenant sont il est vrai plus lentes que les  
 * fonctions originales mais elles fonctionnent.  
 */

function integer(n) { return n % (0xffffffff + 1); }

function shr(a, b) {
    a = integer(a);
    b = integer(b);
    if (a - 0x80000000 >= 0) {
        a = a % 0x80000000;
        a >>= b;
        a += 0x40000000 >> (b - 1);
    } else
        a >>= b;
    return a;
}

function shl1(a) {
    a = a % 0x80000000;
    if (a & 0x40000000 == 0x40000000) {
        a -= 0x40000000;
        a *= 2;
        a += 0x80000000;
    } else
        a *= 2;
    return a;
}

function shl(a, b) {
    a = integer(a);
    b = integer(b);
    for (var i = 0; i < b; i++) a = shl1(a);
    return a;
}

function and(a, b) {
    a = integer(a);
    b = integer(b);
    var t1 = (a - 0x80000000);
    var t2 = (b - 0x80000000);
    if (t1 >= 0)
        if (t2 >= 0)
            return ((t1 & t2) + 0x80000000);
        else
            return (t1 & b);
    else
        if (t2 >= 0)
            return (a & t2);
        else
            return (a & b);
}

function or(a, b) {
    a = integer(a);
    b = integer(b);
    var t1 = (a - 0x80000000);
    var t2 = (b - 0x80000000);
    if (t1 >= 0)
        if (t2 >= 0)
            return ((t1 | t2) + 0x80000000);
        else
            return ((t1 | b) + 0x80000000);
    else
        if (t2 >= 0)
            return ((a | t2) + 0x80000000);
        else
            return (a | b);
}

function xor(a, b) {
    a = integer(a);
    b = integer(b);
    var t1 = (a - 0x80000000);
    var t2 = (b - 0x80000000);
    if (t1 >= 0)
        if (t2 >= 0)
            return (t1 ^ t2);
        else
            return ((t1 ^ b) + 0x80000000);
    else
        if (t2 >= 0)
            return ((a ^ t2) + 0x80000000);
        else
            return (a ^ b);
}

function not(a) {
    a = integer(a);
    return (0xffffffff - a);
}

/* D¨¦but de l'algorithme */

var state = new array(4);
var count = new array(2);
count[0] = 0;
count[1] = 0;
var buffer = new array(64);
var transformBuffer = new array(16);
var digestBits = new array(16);

var S11 = 7;
var S12 = 12;
var S13 = 17;
var S14 = 22;
var S21 = 5;
var S22 = 9;
var S23 = 14;
var S24 = 20;
var S31 = 4;
var S32 = 11;
var S33 = 16;
var S34 = 23;
var S41 = 6;
var S42 = 10;
var S43 = 15;
var S44 = 21;

function F(x, y, z) {
    return or(and(x, y), and(not(x), z));
}

function G(x, y, z) {
    return or(and(x, z), and(y, not(z)));
}

function H(x, y, z) {
    return xor(xor(x, y), z);
}

function I(x, y, z) {
    return xor(y, or(x, not(z)));
}

function rotateLeft(a, n) {
    return or(shl(a, n), (shr(a, (32 - n))));
}

function FF(a, b, c, d, x, s, ac) {
    a = a + F(b, c, d) + x + ac;
    a = rotateLeft(a, s);
    a = a + b;
    return a;
}

function GG(a, b, c, d, x, s, ac) {
    a = a + G(b, c, d) + x + ac;
    a = rotateLeft(a, s);
    a = a + b;
    return a;
}

function HH(a, b, c, d, x, s, ac) {
    a = a + H(b, c, d) + x + ac;
    a = rotateLeft(a, s);
    a = a + b;
    return a;
}

function II(a, b, c, d, x, s, ac) {
    a = a + I(b, c, d) + x + ac;
    a = rotateLeft(a, s);
    a = a + b;
    return a;
}

function transform(buf, offset) {
    var a = 0, b = 0, c = 0, d = 0;
    var x = transformBuffer;

    a = state[0];
    b = state[1];
    c = state[2];
    d = state[3];

    for (var i = 0; i < 16; i++) {
        x[i] = and(buf[i * 4 + offset], 0xff);
        for (var j = 1; j < 4; j++) {
            x[i] += shl(and(buf[i * 4 + j + offset], 0xff), j * 8);
        }
    }

    /* tour 1 */
    a = FF(a, b, c, d, x[0], S11, 0xd76aa478); /* 1 */
    d = FF(d, a, b, c, x[1], S12, 0xe8c7b756); /* 2 */
    c = FF(c, d, a, b, x[2], S13, 0x242070db); /* 3 */
    b = FF(b, c, d, a, x[3], S14, 0xc1bdceee); /* 4 */
    a = FF(a, b, c, d, x[4], S11, 0xf57c0faf); /* 5 */
    d = FF(d, a, b, c, x[5], S12, 0x4787c62a); /* 6 */
    c = FF(c, d, a, b, x[6], S13, 0xa8304613); /* 7 */
    b = FF(b, c, d, a, x[7], S14, 0xfd469501); /* 8 */
    a = FF(a, b, c, d, x[8], S11, 0x698098d8); /* 9 */
    d = FF(d, a, b, c, x[9], S12, 0x8b44f7af); /* 10 */
    c = FF(c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
    b = FF(b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
    a = FF(a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
    d = FF(d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
    c = FF(c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
    b = FF(b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

    /* tour 2 */
    a = GG(a, b, c, d, x[1], S21, 0xf61e2562); /* 17 */
    d = GG(d, a, b, c, x[6], S22, 0xc040b340); /* 18 */
    c = GG(c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
    b = GG(b, c, d, a, x[0], S24, 0xe9b6c7aa); /* 20 */
    a = GG(a, b, c, d, x[5], S21, 0xd62f105d); /* 21 */
    d = GG(d, a, b, c, x[10], S22, 0x2441453); /* 22 */
    c = GG(c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
    b = GG(b, c, d, a, x[4], S24, 0xe7d3fbc8); /* 24 */
    a = GG(a, b, c, d, x[9], S21, 0x21e1cde6); /* 25 */
    d = GG(d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
    c = GG(c, d, a, b, x[3], S23, 0xf4d50d87); /* 27 */
    b = GG(b, c, d, a, x[8], S24, 0x455a14ed); /* 28 */
    a = GG(a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
    d = GG(d, a, b, c, x[2], S22, 0xfcefa3f8); /* 30 */
    c = GG(c, d, a, b, x[7], S23, 0x676f02d9); /* 31 */
    b = GG(b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

    /* tour 3 */
    a = HH(a, b, c, d, x[5], S31, 0xfffa3942); /* 33 */
    d = HH(d, a, b, c, x[8], S32, 0x8771f681); /* 34 */
    c = HH(c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
    b = HH(b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
    a = HH(a, b, c, d, x[1], S31, 0xa4beea44); /* 37 */
    d = HH(d, a, b, c, x[4], S32, 0x4bdecfa9); /* 38 */
    c = HH(c, d, a, b, x[7], S33, 0xf6bb4b60); /* 39 */
    b = HH(b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
    a = HH(a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
    d = HH(d, a, b, c, x[0], S32, 0xeaa127fa); /* 42 */
    c = HH(c, d, a, b, x[3], S33, 0xd4ef3085); /* 43 */
    b = HH(b, c, d, a, x[6], S34, 0x4881d05); /* 44 */
    a = HH(a, b, c, d, x[9], S31, 0xd9d4d039); /* 45 */
    d = HH(d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
    c = HH(c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
    b = HH(b, c, d, a, x[2], S34, 0xc4ac5665); /* 48 */

    /* tour 4 */
    a = II(a, b, c, d, x[0], S41, 0xf4292244); /* 49 */
    d = II(d, a, b, c, x[7], S42, 0x432aff97); /* 50 */
    c = II(c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
    b = II(b, c, d, a, x[5], S44, 0xfc93a039); /* 52 */
    a = II(a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
    d = II(d, a, b, c, x[3], S42, 0x8f0ccc92); /* 54 */
    c = II(c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
    b = II(b, c, d, a, x[1], S44, 0x85845dd1); /* 56 */
    a = II(a, b, c, d, x[8], S41, 0x6fa87e4f); /* 57 */
    d = II(d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
    c = II(c, d, a, b, x[6], S43, 0xa3014314); /* 59 */
    b = II(b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
    a = II(a, b, c, d, x[4], S41, 0xf7537e82); /* 61 */
    d = II(d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
    c = II(c, d, a, b, x[2], S43, 0x2ad7d2bb); /* 63 */
    b = II(b, c, d, a, x[9], S44, 0xeb86d391); /* 64 */

    state[0] += a;
    state[1] += b;
    state[2] += c;
    state[3] += d;

}
/* Avec l'initialisation de  Dobbertin:  
   state[0] = 0x12ac2375;  
   state[1] = 0x3b341042;  
   state[2] = 0x5f62b97c;  
   state[3] = 0x4ba763ed;  
   s'il y a une collision:  
 
   begin 644 Message1  
   M7MH=JO6_>MG!X?!51$)W,CXV!A"=(!AR71,<X`Y-IIT9^Z&8L$2N'Y*Y:R.;  
   39GIK9>TF$W()/MEHR%C4:G1R:Q"=  
   `  
   end  
 
   begin 644 Message2  
   M7MH=JO6_>MG!X?!51$)W,CXV!A"=(!AR71,<X`Y-IIT9^Z&8L$2N'Y*Y:R.;  
   39GIK9>TF$W()/MEHREC4:G1R:Q"=  
   `  
   end  
*/
function init() {
    count[0] = count[1] = 0;
    state[0] = 0x67452301;
    state[1] = 0xefcdab89;
    state[2] = 0x98badcfe;
    state[3] = 0x10325476;
    for (var i = 0; i < digestBits.length; i++)
        digestBits[i] = 0;
}

function update(b) {
    var index, i;

    index = and(shr(count[0], 3), 0x3f);
    if (count[0] < 0xffffffff - 7)
        count[0] += 8;
    else {
        count[1]++;
        count[0] -= 0xffffffff + 1;
        count[0] += 8;
    }
    buffer[index] = and(b, 0xff);
    if (index >= 63) {
        transform(buffer, 0);
    }
}

function finish() {
    var bits = new array(8);
    var padding;
    var i = 0, index = 0, padLen = 0;

    for (i = 0; i < 4; i++) {
        bits[i] = and(shr(count[0], (i * 8)), 0xff);
    }
    for (i = 0; i < 4; i++) {
        bits[i + 4] = and(shr(count[1], (i * 8)), 0xff);
    }
    index = and(shr(count[0], 3), 0x3f);
    padLen = (index < 56) ? (56 - index) : (120 - index);
    padding = new array(64);
    padding[0] = 0x80;
    for (i = 0; i < padLen; i++)
        update(padding[i]);
    for (i = 0; i < 8; i++)
        update(bits[i]);

    for (i = 0; i < 4; i++) {
        for (var j = 0; j < 4; j++) {
            digestBits[i * 4 + j] = and(shr(state[i], (j * 8)), 0xff);
        }
    }
}

/* Fin de l'algorithme MD5 */

function hexa(n) {
    var hexa_h = "0123456789abcdef";
    var hexa_c = "";
    var hexa_m = n;
    for (var hexa_i = 0; hexa_i < 8; hexa_i++) {
        hexa_c = hexa_h.charAt(Math.abs(hexa_m) % 16) + hexa_c;
        hexa_m = Math.floor(hexa_m / 16);
    }
    return hexa_c;
}


var ascii = "01234567890123456789012345678901" +
    " !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
    "[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~";

function MD5(message) {
    var l, s, k, ka, kb, kc, kd;

    init();
    for (var k = 0; k < message.length; k++) {
        l = message.charAt(k);
        update(ascii.lastIndexOf(l));
    }
    finish();
    ka = kb = kc = kd = 0;
    for (var i = 0; i < 4; i++) ka += shl(digestBits[15 - i], (i * 8));
    for (var i = 4; i < 8; i++) kb += shl(digestBits[15 - i], ((i - 4) * 8));
    for (var i = 8; i < 12; i++) kc += shl(digestBits[15 - i], ((i - 8) * 8));
    for (var i = 12; i < 16; i++) kd += shl(digestBits[15 - i], ((i - 12) * 8));
    s = hexa(kd) + hexa(kc) + hexa(kb) + hexa(ka);
    return s;
}  

module.exports = {
    MD5:MD5
}